When　the　high-speed　hydraulic　cylinder　drives　the　parts　to　the　stroke　terminal,　it　is　often　accompanied　by　strong　hydraulic　shock.　Cushioning　is　an　important　aspect　in　hydraulic　cylinder　performance,　which　can　greatly　reduce　the　vibration,　noise　and　temperature　rise　of　oil　caused　by　hydraulic　shock.　In　this　paper,　we　presented　a　variable　annular　gap　cushioning　for　hydraulic　cylinder.　Firstly,　the　working　principle　of　the　variable　annular　gap　cushioning　in　hydraulic　cylinder　is　provided.　Secondly,　the　mathematical　model　and　geometric　model　of　the　hydraulic　cylinder　are　established,　and　the　dynamic　CFD　simulation　of　the　hydraulic　cylinder　is　conducted.　Based　on　the　pressure　and　velocity　characteristics　of　the　hydraulic　cylinder　under　different　cushioning　parameters,　the　optimal　structural　parameters　of　the　variable　annular　gap　cushioning　can　be　determined.　In　addition,　the　simulation　results　show　that　the　pressure　peak　value　and　pressure　fluctuation　obviously　decrease　under　the　optimal　structural　parameters　of　cushioning.　The　proposed　cushion　structure　and　numerical　results　have　scientific　and　engineering　value　to　promote　the　innovative　development　of　hydraulic　cylinder.　©　2019　IEEE.